The mechanism of corrosion of various types of dental amalgam, and the effects of corrosion on mechanical properties as a function of amalgam composition, structure, and corrosion conditions will be studied in vitro. Amalgam specimens of various compositions will be exposed to a chloride environment at body temperature under conditions of general, crevice, and galvanic corrosion. Following the exposures the specimens will be examined using optical metallography, SEM, electron microprobe, and other analytical techniques to determine the structural changes. Compressive strength and creep will be determined as a function of the time of exposure. A comprehensive examination of the amalgam samples using electrochemical techniques will be made and the results will be correlated with the observed effects on structure and mechanical properties. Corrosion in special simulated localized cells will be studied to determine the electrochemical conditions including potentials, current, and solution chemistry changes.